The cathode current collector of a battery serves several functions. One of the functions is to conduct the flow of electrons between the active material of the electrode and the battery terminals. Cathode current collectors may also provide some support for the cathode active material. Cathode current collector materials must maintain chemical stability and mechanical integrity in corrosive electrolytes throughout cell life. However, this is often a problem, since the availability of materials Capable of meeting such requirements is limited.
Current collectors in use today, consist of either a metal foil or a metal mesh, and the metal is typically nickel, stainless steel or aluminum. These materials contribute significantly to both the weight and volume of the battery. They do not contribute to the energy content since they are inactive materials. Consequently, the use of metal foil current collectors reduces the volumetric and gravimetric energy density of a battery as compared to what the energy density would have been if less dense and more highly conductive materials were available. In addition, under battery operating conditions, corrosion of the cathode metal current collector occurs. Such metal foil current collectors electrochemically dissolve and this is particularly a problem if thin current collectors are used in an attempt to improve energy density values. Corrosion of typical metal current collectors often leads to loss of contact, electronic isolation and, consequently, to poor battery performance.
Therefore, what is needed is a cell construction and method of operation which overcome problems with cathode current collector corrosion and which provide a less expensive, light weight cell having more attractive electronic conductivity properties.